Laryngoscopes are medical devices in common use in oral and tracheal medical procedures, and may be used to obtain view of the glottis or larynx, or to manipulate the tongue, glottis or larynx in order to facilitate insertion of endotracheal tubes or other instruments such as endoscopes, which may be separate pieces of equipment, or may be integral to a laryngoscope.
A laryngoscope typically comprises an insertion section, which is an elongate section which extends towards and into a patient's oral cavity during a medical procedure such as intubation. A laryngoscope insertion section is typically connected to (integrally or removably) to a body, which usually functions as a handle or is demountably attachable to an insertion section in which the handle and the part which extend into a patient's oral cavity in use are integrated.
Some known laryngoscope insertion sections, such as Miller or Wisconsin insertion sections, are substantially flat. However, the insertion section of a laryngoscope is more commonly bent to better enter through a patient's oropharynx towards their larynx. Some known insertion sections include first and second straight portions, with a bend therebetween, or are curved, at least in part.
Within this specification and the appended claims, the inferior surface is the surface of an insertion section which faces the patient's tongue in use. Accordingly, the inferior surface is not defined by ancillary features of a laryngoscope insertion section, such as means for mechanically securing a proximal portion to a laryngoscope body, tube guiding elements extending laterally from the insertion section and/or any surfaces of an endotracheal tube secured to a tube guide.
The opposite surface is referred to as the superior surface. Words such as inferior, inferiorly, superior and superiorly are used in corresponding senses. A superior-inferior axis is a virtual axis extending parallel to the superior and inferior directions.
The words distal and distally refer to being towards the end of the insertion section which extends towards a patient's trachea in use and the words proximal and proximally refer to being towards the person carrying out the medical procedure, in use.
By depth, or thickness, we mean the distance, at any point along the length of the laryngoscope insertion section, between the inferior surface and the superior surface.
By width we mean the distance across the laryngoscope insertion section perpendicular to the main proximal-distal axis of the insertion section (i.e. the axis along the length of the insertion section), parallel to the inferior or superior surface, as the case may be.
By laterally we mean generally perpendicular to the proximal-distal axis of the insertion section.
In order to ensure sterility, and to obviate the need to repeatedly sterilise the entire laryngoscope, insertion sections of modern laryngoscopes are frequently removable and for example comprise a disposable protective cover for hardware such as cameras, image guides, light sources etc., and which is securable to the laryngoscope body, for example, to a hardware containing member extending from the body, or around the body, or a part thereof.
In order to minimize trauma to the patient and to provide the maximum room for further medical apparatus to be introduced into the oral cavity or airway, the size of the laryngoscope and in particular the laryngoscope insertion section is advantageously kept to a minimum, particularly the distal portion of the insertion section.
Additionally, since laryngoscopic procedures may require some forceful manipulation of the laryngoscope, it is additionally desirable that the insertion section and the medical instrument as a whole, be both light weight and mechanically robust.
Thus, whereas it is possible to produce robust insertion sections, strength may be at the expense of light weight and large dimensions, and whereas it has been possible to produce comparatively slimline insertion sections, this has been at the expense of durability or suitability for certain procedures and it is known for disposable laryngoscope insertion sections to be either prone to cracking during use, requiring replacement of the disposable portion, or worse resulting in injury or increased risk of infection, or sufficiently large as to be difficult to work with. Furthermore, if the insertion section bends too much under excessive force, the view of the larynx may be compromised.